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| Titel |
Long-term trend and variability of atmospheric PM10 concentration in the Po Valley |
| VerfasserIn |
A. Bigi, G. Ghermandi |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 10 ; Nr. 14, no. 10 (2014-05-20), S.4895-4907 |
| Datensatznummer |
250118723
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| Publikation (Nr.) |
 copernicus.org/acp-14-4895-2014.pdf |
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| Zusammenfassung |
| The limits to atmospheric pollutant concentration set by the
European Commission provide a challenging target for the
municipalities in the Po Valley, because of the characteristic
climatic conditions and high population density of this region. In
order to assess climatology and trends in the concentration of
atmospheric particles in the Po Valley, a data set of PM10
data from 41 sites across the Po Valley have been analysed,
including both traffic and background sites (either urban, suburban
or rural). Of these 41 sites, 18 with 10 yr or longer record
have been analysed for long-term trend in deseasonalized monthly
means, in annual quantiles and in monthly frequency distribution.
A widespread significant decreasing trend has been observed at most
sites, up to a few percent per year, by a generalized least squares and
Theil–Sen method. All 41 sites have been tested for significant
weekly periodicity by Kruskal–Wallis test for mean anomalies and by
Wilcoxon test for weekend effect magnitude. A significant weekly
periodicity has been observed for most PM10 series,
particularly in summer and ascribed mainly to anthropic particulate
emissions. A cluster analysis has been applied in order to highlight
stations sharing similar pollution conditions over the reference
period. Five clusters have been found, two encompassing the
metropolitan areas of Turin and Milan and their respective nearby
sites and the other three clusters gathering northeast, northwest
and central Po Valley sites respectively. Finally, the observed
trends in atmospheric PM10 have been compared to trends in
provincial emissions of particulates and PM precursors, and analysed
along with data on vehicular fleet age, composition and fuel
sales. A significant basin-wide drop in emissions occurred for gaseous
pollutants, contrarily to emissions of PM10 and
PM2.5, whose drop was low and restricted to a few
provinces. It is not clear whether the decrease for only gaseous
emissions is sufficient to explain the observed drop in atmospheric
PM10, or if the low drop in particulate emissions is
indeed due to the uncertainty in the emission inventory data for
this species. |
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